The Contractor, in pursuit of licensure and in accordance with the FDA Animal Rule, will develop circular fibroblast growth factor-peptide (FGF-P), a proposed bio-better of FgF-2, as a mitigation agent for radiation-induced GI toxicity. FGF-P acts through a variety of mechanisms, including decreased cell loss and improved proliferation of small bowel mucosa, improved gut barrier function with reduced bacterial translocation, and support of bone marrow with induction of granulocyte-colony stimulating factor (G-CSF).